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Kura

Kura(蔵 — 宝物を守る倉)

AIエージェントのためのローカルEVMウォレット。 MacでClaudeのようなAIがインターネット決済(x402)をするとき、人間がパスワードで承認するウォレットです。

  • 人間用ウォレット(MetaMaskなど)ではなくAIエージェント用

  • クラウドSaaSではない — ローカルのみで動作します。鍵はこのコンピュータから出て行きません。

  • AIが決済を要求 → 人間がパスワードで承認 → 実行

  • チェーンはBase(イーサリアムL2、手数料ほぼゼロ)。デフォルトはテストネット(Base Sepolia)


一目でわかる

[ AI 앱 (Claude Code / 데스크톱) ]
        │  MCP로 "결제해줘" 요청
        ▼
[ Kura 데스크톱 앱 ]  ← 승인 팝업 → 사람이 비밀번호 입력
        │  서명 (키는 이 앱 안에서만)
        ▼
[ Base 체인 / x402 페이실리테이터 ]  ← 실제 결제

パスワードはKuraアプリの入力欄でのみ受け付けます。チャット画面・MCP・設定ファイルのどこにも入りません。


Related MCP server: cardzero-mcp

インストール

Apple Silicon Mac(macOS 11以上)

(A) Homebrew

brew install --cask dinggi5/tap/kura

(B) DMGを直接ダウンロード

ReleasesからKura_<バージョン>_aarch64.dmgをダウンロードして開き、KuraをApplicationsフォルダにドラッグ&ドロップしてください。

鍵を預けるアプリなので、受け取ったアプリが本当に私が作ったものか確認する方法はSECURITY.mdにコマンドまで書いてあります。

(C) ソースからビルド

事前準備: Rust、Node.js(20.19+ または 22.12+ — Vite 7が必要)、macOS。

git clone https://github.com/dinggi5/kura.git
cd kura
git checkout v0.1.1   # 배포본과 같은 소스. 빼면 개발 중인 최신 코드가 받아져요
npm ci                # package-lock.json 그대로 설치 (install 은 버전이 올라갈 수 있어요)

# 개발 모드로 바로 실행
npm run tauri dev

# 앱으로 빌드해 /Applications에 설치
npm run tauri build -- --bundles app --no-sign
ditto src-tauri/target/release/bundle/macos/Kura.app /Applications/Kura.app
open /Applications/Kura.app

アップデート

アプリが自動でアップデートします。
設定 → 情報でバージョンと変更内容を確認し、今すぐインストールして再起動を押してください。

  • 確認だけが自動で、インストールは常に自分で押す必要があります。

  • 受け取ったファイルは署名が正しいか検証した後でのみインストールされます(署名検証は無効にできません)。詳細はSECURITY.mdの「アップデート」節に書いてあります。

  • 自動アップデート確認の通信が嫌なら設定 → 情報 → 起動時に確認をオフにしてください。

削除

⚠️ アプリを削除してもウォレットは削除されません。 鍵・設定・取引履歴はアプリの外の~/.jigapフォルダにあるため、アプリだけ削除するとそのまま残ります — うっかり資産を失わないように意図的にそうしています(brew uninstall --zapでも削除されません)。

# 앱만 제거 (지갑은 남음 — 나중에 다시 설치하면 그대로 이어서 써요)
brew uninstall --cask dinggi5/tap/kura   # 또는 /Applications/Kura.app 을 휴지통으로

このMacでウォレットまで完全に削除するには、順序を必ず守ってください:

  1. 12語のリカバリーフレーズが手元にあるか先に確認してください。 アプリのヘッダーの鍵ボタンから再度確認できます。

  2. 残高が残っているなら他のウォレットに移してください。

  3. Kuraを完全に終了してください(メニューバーアイコンを右クリック → 終了)。起動していると数秒ごとに~/.jigapに状態ファイルを書き込むため、削除したフォルダがすぐに再作成されます。

  4. Kura MCPを接続しているAIツール(Claude Codeなど)も終了してください。

  5. 自動起動をオンにしていたらオフにするか、rm ~/Library/LaunchAgents/Kura.plist(アプリをゴミ箱に捨ててもこのファイルは残ります。brew uninstall --caskで削除すると一緒に削除されます)。

  6. そのあとにrm -rf ~/.jigap

12語なしで最後のrm -rf ~/.jigapを実行すると、そのウォレットの資産は誰にも取り戻せません。


初回起動

Kuraはメニューバーに常駐します。 起動すると画面上部のメニューバーに倉のアイコン(◻︎)が表示され、ウィンドウはそのアイコンをクリックしたときだけ下に展開されます。他の場所をクリックすると閉じ、アプリはバックグラウンドに残ってAIの決済要求を待ち続けます。完全に終了するにはアイコンを右クリック → 終了。(ウォレットがまだない初回起動時はウィンドウが自動で開きます。)

  1. ウォレット作成 — 送金のたびに入力するパスワード(8文字以上)を決めます。このパスワードで鍵が暗号化されて保存されます(~/.jigap/wallet.enc)。

  2. シードのバックアップ — 12語が表示されます。これが資産の本当の所有証明なので、紙やパスワードマネージャーに書き留めてください。パスワードを忘れても12語があれば取り戻せます: アプリを終了し、12語が手元にあるか先に確認したうえで、~/.jigap/wallet.encを削除してアプリを再起動すると、最初の画面のインポートで復元できます(他の標準BIP-39ウォレットに入れても構いません)。ただし、12語なしでこのファイルを削除すると資産を永遠に失います。

  3. ウェルカムツアー — チャージ・AI接続・安全装置を説明します。ヘッダーの**ⓘ ヘルプ**からいつでも再度見られます。


資金を入れる(USDC)

決済するにはウォレットにUSDC(デジタルドル)が必要です。

  • アプリで受け取りを押すとアドレスとQRが表示されます。

  • 取引所・他のウォレットから送る際は必ずBaseネットワークを選択してください。他のネットワークに送ると資金を失います。

  • **テストネット(デフォルト)**では本物のお金ではありません。受け取り画面のFaucetボタンで無料のテストコインを受け取って練習してください。

  • ETHは任意です — x402決済は手数料をペイフェシリテーターが代わりに支払うため、ETHが0でも大丈夫です。アプリの送金で直接送金するときだけガス用のETHが少し必要です(Baseの手数料は1セント前後)。チャージはUSDCだけで十分です。


AI(Claude)に接続する

AIアプリのMCP設定にKuraサーバーを登録すると接続されます。接続されるとメイン画面に**「Claude接続済み」バッジが表示されます。0.1.2からはアプリ内にMCPサーバーが組み込まれているため**、ソースのクローンやRustのインストールなしで接続できます。

一番簡単な方法 — アプリ内の「AI接続」画面

メイン画面上部の**「AI未接続」バッジをクリックすると**接続画面が開きます。

  • Claudeデスクトップ — 「接続」ボタンを押すとClaudeに拡張機能のインストール画面が表示されます。「インストール」を押すだけです。

  • Claude Code — ボタン一つで登録されます(claude mcp addをアプリが代わりに実行)。次のclaude起動からどのフォルダでも接続されます。

以下は同じことを手動で行う方法です。

Claudeデスクトップ — 拡張ファイル一つで完了

リリースページからkura-<バージョン>.mcpbをダウンロードしてダブルクリックすると、Claudeデスクトップがインストールを確認してきます。(またはClaude設定 → 拡張機能 → ファイルを選択。)

拡張機能の中に実行ファイルはありません — インストール済みのKura.app内の署名・公証済みMCPサーバーを署名確認後に実行するランチャーだけが入っています。そのためKuraアプリを先にインストールする必要があります。

Claude Code・他のMCPアプリ

アプリ内のバイナリを絶対パスで登録すればいいです:

claude mcp add --scope user kura -- /Applications/Kura.app/Contents/MacOS/kura-mcp

(--scope userは「このフォルダだけ」ではなくどこでも使えるようにするオプションです。1つのプロジェクトだけで使うなら外しても構いません。)

他のMCPアプリは設定に以下のように記述します:

{
  "mcpServers": {
    "kura": {
      "command": "/Applications/Kura.app/Contents/MacOS/kura-mcp"
    }
  }
}

ソースから開発中の場合

リポジトリルートの.mcp.jsonがすでに入っています。このフォルダでclaudeを実行すると自動で認識されます(最初にサーバーを使うか聞かれるので承認してください)。このパスはcargo runで毎回新しくビルドする開発用です — インストールして使う場合は上記のアプリパス登録が正しいです。

AIが使えるツール: get_wallet_status・get_balances・get_history(読み取り専用)・request_payment(決済要求 → アプリの承認ポップアップ)・x402_fetch(402決済がかかったURLを呼び出し)。

MCPツールを変更したらAIアプリを再起動する必要があります(サーバーはセッション開始時に1回ロードされます)。


決済はこう流れます

  1. AIが決済を要求します。

  2. Kuraのウィンドウが表示され、いくらを、どこへ送るのかを見せます(ウィンドウが隠れていても自動で表示されます)。

  3. パスワードを入力して承認します。

  4. 決済が実行され、結果がAIに返ります。5分以内に承認しないと自動拒否。


セキュリティモデル

  • パスワード承認 — デフォルトは毎回の決済でパスワード承認です(自動決済をオンにすると以下の条件でのみ例外)。鍵は暗号化(Argon2id + AES-256-GCM)されて保存され、決済するときだけ復号化してすぐ消去します(自動決済セッションをオンにすると、ロック解除中のみメモリに保持)。

  • 限度額 — 1回に/1日にいくらまで送れるかを設定で決めます(デフォルト単一5・日次20 USDC)。超えるとブロックされます。

  • 緊急ロック — ヘッダーのシールドボタンをオンにすると、すべての送金が即座にブロックされます。

  • 信頼アドレス・自動決済 — パスワードなしで自動承認するにはセッションロック解除 + 少額限度 + 信頼アドレスの3つすべてが揃わなければなりません。それ以外は常にパスワード。

  • 取引履歴 — 送った送金・ブロックされた試行・署名をすべて記録します。

  • ローカル優先 — 鍵(~/.jigap/)はリポジトリの外にあり、gitに上がりません。

  • 分析・フォントCDNなし — アプリが自らインターネットに接続するのは3つだけです。①残高照会・送金に使うRPCサーバー ②AIが要求したx402アドレス ③アップデート確認(GitHub)。使用履歴はどこにも送信されず、フォントもアプリ内に入っているのでオフラインでも画面はそのまま表示されます。

  • アップデート確認はオフにできます — アプリ起動時にGitHubへ新しいバージョンがあるか問い合わせます(そこには接続IPと現在のバージョンが残ります)。設定 → 情報 → 起動時に確認でオフにするとこの通信もなくなります。確認をオンにしていてもオフにしていても、インストールは自分で押さないと進みません — こっそり変更されることはありません。


開発者向け

CLIのkuraでも同じウォレットを操作できます(MCPサーバーとコアロジックを共有)。インストール済みアプリにすでに入っているので、PATHに1行追加すればすぐ使えます:

sudo mkdir -p /usr/local/bin
sudo ln -sf /Applications/Kura.app/Contents/MacOS/kura-cli /usr/local/bin/kura
kura status

ソースから実行する場合:

cargo run --manifest-path ./kura-mcp/Cargo.toml --bin kura -- status
cargo run --manifest-path ./kura-mcp/Cargo.toml --bin kura -- balance
cargo run --manifest-path ./kura-mcp/Cargo.toml --bin kura -- history --limit 10
cargo run --manifest-path ./kura-mcp/Cargo.toml --bin kura -- pay <주소> <금액> --token usdc
cargo run --manifest-path ./kura-mcp/Cargo.toml --bin kura -- fetch <URL>

pay/fetchはパスワードをCLIで受け取りません — Kuraアプリが起動している必要があり、承認ポップアップで人間がパスワードを入力します。

テスト:

(cd src-tauri && cargo test)        # 백엔드(지갑·암호화·한도·송금)
(cd kura-mcp && cargo test)         # MCP/CLI 어댑터
npx tsc --noEmit && npx vite build  # 프론트

配布物(署名・公証済みDMG)を作成する手順は**docs/RELEASE.md**にあります。Apple Developerアカウントと1回の設定が必要で、その後は1行です:

./scripts/release.sh

技術スタック

デスクトップ

Tauri (Rust + ウェブフロント)

フロント

React + Tailwind CSS, Framer Motion, Lucide, Pretendard

チェーン

Base / alloy-rs

決済

x402 (EIP-3009 オフチェーン署名)

AI接続

MCPサーバー (rmcp)

構造: [Rustコア(src-tauri)] ← MCP / CLIアダプター(kura-mcp)。鍵へのアクセス(署名)はGUIプロセスのみ — それが最終防衛線です。


ライセンス・ステータス

MITライセンス — 鍵とお金を扱うコードなので、直接読んで検証し、修正できるべきだと考えています。

脆弱性を発見した場合は、イシューとして上げる前に**SECURITY.mdの非公開パスでお知らせください。同じ文書にKuraが防げないこと**も書いてあります。

同梱のPretendardフォントはSIL Open Font License 1.1です(全文)。

最優先ユーザーは自分自身 — Apple Silicon MacでローカルLLM/Claudeで決済する韓国の開発者・クリエイターのためのウォレットです。まだ0.1.x初期バージョンなので、デフォルトのテストネットで先に慣れてから、メインネットには失ってもいい分だけ入れることをお勧めします。

Available Tools

7 tools
get_balancesBalancesA
Read-only

Reads the active account's USDC (for payments) and gas-token balances on the active network (Base mainnet, Arc mainnet, Base Sepolia, or Arc testnet, per the user's setting). The eth field is the gas balance and is ABSENT on chains where gas is paid in USDC itself (Arc) — there the USDC balance already covers gas, so never add the two together. Errors if there is no wallet.

NameRequiredDescriptionDefault

No parameters

TDQS

A4.1/5.0
Behavior4/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint=true and openWorldHint=true, so safety is covered; the description goes further by disclosing the no-wallet error case and a critical cross-field caveat (the `eth` gas field is absent on Arc and must never be added to the USDC balance). It does not cover rate limits or refresh/freshness behavior, so it stops short of a 5.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Three sentences, front-loaded with the core read action, followed by the field caveat and the error case. The parenthetical enumeration of the four networks is slightly heavy but genuinely useful since it defines the valid scope; nearly every sentence earns its place.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

With no parameters and no output schema, the description carries the burden of explaining the return shape, and it does so reasonably: it names the two balance types, flags the missing `eth` field per chain, and states the error case. Minor gap is freshness/caching and what happens across multiple networks at once.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The tool takes zero parameters, so the baseline is 4. The description's field-level discussion (USDC vs `eth` gas balance and their relationship on Arc) concerns returned values rather than inputs, but it does add interpretive value that the empty schema cannot.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb ('Reads') and resource (USDC and gas-token balances) for the active account, and pins the scope to the active network with named chains. An agent can immediately distinguish this from get_wallet_status or get_history without opening a schema.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines3/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Usage is implied by the purpose but never stated as when-to-use or when-not-to-use, and no sibling tool is named as an alternative. The only routing signal is the failure condition ('Errors if there is no wallet'), which is a precondition rather than guidance on choosing this tool.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

get_historyHistoryA
Read-only

Returns the active account's recent transaction attempts, newest first. status is one of sent, blocked, failed, signed (x402 signed, awaiting settlement), settled (x402 settled, settle_tx is the settlement tx), settle_failed, unknown (a signed transaction was submitted but the wallet couldn't confirm the chain received it — detail is its tx hash; it may have gone through, so never resend on the strength of this entry alone; the wallet app later rechecks it on-chain and turns it into sent or reverted), reverted (mined but reverted on-chain — no money moved, only gas), expired (an x402 signature that was never used before it expired — no money moved), or received (money that came in — to is the sender, detail the tx hash; both are empty for ETH a contract sent; found on-chain by the wallet app while it runs, back to 90 days). Use limit to cap how many come back (default 20).

NameRequiredDescriptionDefault
limitNoHow many recent entries to return (default 20, max 200).

TDQS

A4.2/5.0
Behavior5/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations only declare readOnlyHint and openWorldHint; the description carries substantial extra behavior: per-status meaning, which statuses mean no money moved (reverted, expired), that 'unknown' may have gone through and the wallet rechecks it on-chain, that 'received' comes from an app-driven on-chain scan back to 90 days. This is exactly the context annotations cannot supply.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The core purpose is front-loaded and every clause carries information — the status enumeration is necessary because there is no output schema. It loses a point because the status glossary is delivered as one very dense run-on sentence rather than a scannable list.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

With no output schema and only one optional parameter, the description fully covers what the agent needs: return ordering, default limit, and the complete semantics of every status value including financial and safety implications. Nothing material is missing.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100% for the single 'limit' parameter, so the schema already documents default 20 and max 200; the description only restates the default. Baseline 3 applies since the schema does the heavy lifting and the description adds no new parameter syntax.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb and resource — 'Returns the active account's recent transaction attempts, newest first' — including scope (active account) and ordering. The resource is unmistakably distinct from siblings like get_balances and get_wallet_status, so an agent can route without opening any schema.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines3/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Usage is implied by the resource and by the embedded warning 'never resend on the strength of this entry alone', which quietly steers the agent away from acting on 'unknown' entries via x402_resubmit. However, it never explicitly says when to call this versus alternatives, nor states prerequisites or exclusions.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

get_wallet_statusWallet statusA
Read-only

Returns the wallet's state and address. state is encrypted (normal), legacy, or none. address is the ACTIVE account's address; accounts lists every account in the wallet (index, address, label) and account is the active index. Balances, history, and payment requests all use the active account, and only the user can switch accounts, in the wallet app. No password needed — read only.

NameRequiredDescriptionDefault

No parameters

TDQS

A4.4/5.0
Behavior5/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint=true and openWorldHint=false, and the description goes well beyond them: it enumerates the state values (encrypted/legacy/none), clarifies that address is the ACTIVE account while accounts lists all accounts, and discloses that only the user can switch accounts in the wallet app. It also reassures no password is needed, which is actionable auth context.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Front-loaded with the core purpose, then structured field-by-field. Every sentence carries information, though the trailing 'No password needed — read only' partially restates the readOnlyHint annotation.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

With zero parameters, no output schema, and annotations covering safety, the description supplies exactly the missing pieces: what fields come back, what the state values mean, and how the active-account concept relates to sibling tools. Nothing an agent needs to call this correctly is absent.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The tool takes zero parameters, so the baseline is 4. The description additionally documents the shape of the returned object (index, address, label, active index), which is useful given no output schema exists, though these are return values rather than input semantics.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb and resource ('Returns the wallet's state and address') and enumerates the exact fields returned (state, address, accounts, account). The sibling set (get_balances, get_history, request_payment) is clearly distinct, and the description anchors its scope to the active account rather than those other resources.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines3/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Usage is implied rather than stated: it explains that balances, history, and payment requests all key off the active account, which tells the agent why it might call this first, but it never explicitly says when to use this tool versus get_balances/get_history, nor names an alternative.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

lookup_agentLook up an agent (ERC-8004)A
Read-only

Reads an agent's ERC-8004 record from the registry on the active network (read-only, on-chain only — the wallet never fetches the agent's website). Give it agent_id, the agent's number in the Identity Registry. Returns: registered, owner, wallet (the registered agentWallet), token_uri and the uri_domain read from it, declared_name (what the record calls itself), and feedback_clients (how many addresses left feedback). Pass pay_to and/or resource to also get a comparison: whether the address equals the registered wallet and whether the resource's domain equals the domain listed on-chain. IMPORTANT: registration is permissionless — anyone can register any name, domain, or wallet, and anyone can leave feedback. Being registered is NOT proof of safety. Only a mismatch is a strong signal, and only when the agent number came from a source you trust (the service's own docs), not from the payment response itself.

NameRequiredDescriptionDefault
pay_toNoOptional: an address to compare against the agent's registered wallet.
agent_idYesThe agent's ERC-8004 number (agentId — the Identity Registry NFT token id).
resourceNoOptional: a resource URL whose domain is compared with the domain listed on-chain.

TDQS

A4.6/5.0
Behavior5/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint and openWorldHint, and the description goes well beyond them: it discloses that nothing is fetched off-chain, that registration is permissionless, and that being registered is not evidence of safety. This is exactly the kind of adversarial-context caveat an agent needs before treating the result as a trust signal.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Front-loads the core action, then the return fields, then the comparison behavior, then the safety caveat. The enumerated return list is long but every item earns its place given there is no output schema. Slightly dense, but no filler sentences.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

With no output schema, the description fully enumerates the returned fields (registered, owner, wallet, token_uri, uri_domain, declared_name, feedback_clients) plus the conditional comparison outputs. For a read-only lookup with three parameters, nothing an agent needs to call or interpret it is missing.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100%, so baseline is 3, but the description adds real semantics: agent_id is the number in the Identity Registry, and pay_to/resource exist specifically to produce address and domain comparisons. That comparison behavior is not derivable from the terse schema property descriptions alone.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb and resource: reads an agent's ERC-8004 record from the on-chain registry on the active network. It immediately scopes what the tool does not reach ("the wallet never fetches the agent's website"), which separates it cleanly from the payment/wallet siblings. An agent can tell what this returns without opening the schema.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Gives concrete invocation guidance (supply agent_id; optionally pass pay_to and/or resource to trigger a comparison) and states the condition under which the result is trustworthy (mismatch only matters when the agent number came from a source you trust). No sibling alternative is named, but the siblings are unrelated domains so the omission is minor. Clear context without explicit when-not-to-call routing.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

request_paymentRequest a paymentA
Destructive

Asks the user to make a payment. The wallet app opens an approval window, and the payment is only sent once the user approves it with their password (it waits up to 5 minutes). The one exception is autopay, which the user turns on themselves — only then can a payment be approved automatically, and only within an unlocked session, a small limit, and a trusted address. Arguments: to (recipient address), amount (decimal string), token (USDC by default, or ETH), memo (what the payment is for — the user reads it to decide, so always fill it in), and optionally agent_id (the recipient's ERC-8004 number, if a service told you one — the wallet then shows the user whether the address matches that agent's registered wallet). Per-payment and daily limits and the emergency lock are enforced by the app. Never send a password as an argument — the user types it in the app. Returns: status, tx_hash, detail, and an explorer link. status is approved (the chain accepted the transfer), rejected or failed (nothing was sent — safe to ask again), or unknown: the user approved but the wallet couldn't confirm whether the transfer reached the chain (tx_hash is set when known). unknown means it MAY have been sent — never ask again on your own; tell the user and have them check the history or the tx.

NameRequiredDescriptionDefault
toYesRecipient address (42 characters, starting with 0x).
memoNoWhat the payment is for — the user reads this in the approval window, so fill it in.
tokenNoToken: "USDC" (default) or "ETH".
amountYesAmount as a decimal string, for example "1.5".
agent_idNoOptional: the recipient's ERC-8004 agent number, if you know it from the service's own documentation or agent card. The wallet reads that agent's on-chain record and tells the user whether the address you are paying is the one registered for that agent. A mismatch is the useful part — a match is not proof of anything, since anyone can register. Leave it out if you don't know it; a wrong number just produces a "no such agent" note.

TDQS

A4.8/5.0
Behavior5/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare destructiveHint=true and idempotentHint=false, but the description adds far more: a 5-minute approval timeout, password-entry-only-in-app, app-enforced per-payment/daily limits and emergency lock, autopay preconditions (unlocked session, small limit, trusted address), and the semantics of approved/rejected/failed/unknown including the no-retry rule on unknown. That is exactly the behavioral disclosure a payment tool needs.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Front-loaded with purpose, then arguments, then return semantics in a logical order. It is long, but the length is justified by the absence of an output schema and the high stakes of an irreversible transfer; each section earns its place.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

With no output schema, the description fully documents the return contract (status, tx_hash, detail, explorer link) and the three status branches, plus the critical unknown-may-have-been-sent caveat. Nothing needed to invoke or handle the result is missing.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100%, so the baseline is 3, but the description adds operative meaning beyond the schema: 'USDC by default', the instruction to always fill in memo because the user reads it, and a caution that agent_id mismatch is the useful signal while a match proves nothing. It largely restates the schema fields, but the added rationale has real value.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb+resource ('Asks the user to make a payment') and immediately distinguishes it from read-only siblings like get_balances/get_history by describing the approval-window flow. An agent can tell this is the mutating spend path without opening the schema.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines5/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Gives explicit when-to-use and when-not-to-act guidance: the approval window is the normal path, autopay is the only auto-approval exception and only under user-enabled conditions, and on 'unknown' the agent must never retry on its own but hand off to the user. This is actionable routing logic, not vague context.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

x402_fetchFetch a paid URL (x402)A
Destructive

Calls an x402 paid API or URL. It sends the request first — GET by default, or the given method (POST, PUT, PATCH, DELETE) with optional headers and a JSON object body; if the server answers 402 Payment Required, it asks the user to approve the required payment (exact scheme, the active network, that chain's USDC) in the wallet app, then sends the SAME request (same method, headers and body) again with the payment header and returns the content. If no payment is required (no 402), it just returns the response. Redirects are not followed once a payment header is attached (nor at all when method, headers or body are given) — a redirect comes back as an error with the new address. Text and JSON come back in body. Binary responses (images, PDF, audio) are saved to a file whose path is in saved_file (with content_type); a PNG/JPEG/GIF/WebP image up to 3 MB is also attached as an image. Text longer than 100,000 characters is cut in body and kept whole in saved_file. If saving takes too long (macOS asking for Downloads access), the result comes back first and saving_file names where the file will appear. Settlement takes one of two shapes, chosen by the server's requirement: a facilitator settles the signed EIP-3009 authorization (no gas from this wallet), or — where gas is paid in USDC itself and the server asks for eip3009-client-broadcast — the wallet broadcasts the transfer itself, so the price AND its gas leave this balance. Approval works exactly as in request_payment (password by default; automatic only when the user has turned autopay on), and the app enforces per-payment and daily limits and the emergency lock. Never send a password as an argument. Arguments: url (required), method, headers, body (JSON object), memo (what the payment is for — the user reads it to decide), agent_id. Returns: payment, paid, status, http_status, body, and amount/pay_to/settlement when paid; on a chain where the wallet broadcasts the payment itself, tx and explorer point at that transaction (both are empty on the facilitator-settled path, where settlement_tx/settlement_explorer carry the transaction the seller reports in its receipt — the seller's word, not checked on-chain by the wallet). IMPORTANT — decide on payment, which says where the money is: "none" = nothing was paid, trying again is safe (declined, no 402, or "reverted": the chain rejected the transfer and only gas was spent); "confirmed" = the money left the wallet; "unknown" = it MAY have left (status pending/unknown, or settlement_failed on the facilitator path, where the server's refusal doesn't prove the facilitator didn't settle). For confirmed and unknown without content, asking again can pay a second time — stop and tell the user, showing the tx (when a tx came back without content, x402_resubmit re-sends its proof without paying again). paid is kept for older callers and is simply payment != "none". Read notice when present, and never retry on an HTTP status alone: after the money moved the server may answer with a fresh 402 challenge that reads as if the payment never happened.

NameRequiredDescriptionDefault
urlYesURL of the paid resource to fetch (http/https).
bodyNoJSON object sent as the request body (not allowed with GET). Content-Type defaults to application/json. The paid retry sends exactly the same body.
memoNoWhat the payment is for — the user reads this in the approval window, so fill it in.
methodNoHTTP method: GET (default), POST, PUT, PATCH or DELETE. Many paid APIs (search, image generation) take POST with a JSON body. The paid retry uses the same method.
headersNoExtra request headers as a JSON object of name → value. Payment headers, Host, Content-Length and connection headers are set by the wallet and are refused here. The paid retry sends the same headers.
agent_idNoOptional: the seller's ERC-8004 agent number, if you know it from the service's own documentation or agent card. The wallet then reads that agent's on-chain record and shows the user whether the payment address and the resource domain match what is registered. Leave it out if you don't know it — a wrong number just produces a "no such agent" note.

TDQS

A4.6/5.0
Behavior5/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations only say destructive/openWorld/non-idempotent, while the description discloses far more: the retry-safety semantics of the `payment` field ('none'/'confirmed'/'unknown'), the double-payment hazard, facilitator vs eip3009-client-broadcast gas behavior, redirect handling under a payment header, the 100k truncation and saved_file behavior, and the warning never to retry on HTTP status alone. This is exactly the value-beyond-annotations the dimension rewards, and the destructiveHint is consistent with money leaving the wallet.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The basic request flow is front-loaded before the settlement and retry-safety detail, and nearly every sentence carries operational or safety weight. It is nevertheless very long for a single tool, with some density that could be tightened, so it stops short of a 5.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

There is no output schema, so the description carries the full burden of explaining returns — and it does: payment/paid/status/http_status/body/amount/pay_to/settlement, tx/explorer vs settlement_tx, and notice. For a 6-param destructive payment tool, an agent has everything needed to call it and interpret the result safely.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100%, so the baseline is 3, but the description adds real meaning: it explains memo is what the user reads to decide, agent_id drives an on-chain ERC-8004 verification note, and it warns never to pass a password as an argument. These are semantic additions beyond the schema text.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The opening sentence gives a specific verb and resource ('Calls an x402 paid API or URL') and the whole description keeps the scope tight around paid HTTP fetching. It distinguishes itself from request_payment by reference ('Approval works exactly as in request_payment') and from x402_resubmit by naming it as the no-pay-again path. An agent can separate it from every sibling without opening a schema.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

It clearly states the triggering condition (server answers 402 → user approval → same request resent), when the tool is a plain fetch (no 402), and routes to x402_resubmit when a tx came back without content. It does not give an explicit 'prefer X over request_payment when...' decision rule, but the surrounding context is strong enough to infer usage.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

x402_resubmitResubmit an x402 payment proofA
Idempotent

Resubmits the on-chain proof of an x402 payment this wallet already broadcast itself, to get the content it paid for. Use it when x402_fetch returned a tx without content (status pending, unknown or undelivered, or settlement_failed with a tx). No new money moves and no approval is asked: the wallet re-sends the same proof (the tx plus the saved challenge values) to the same URL. It first checks the tx on-chain — if it isn't mined yet you get status pending (wait and call again), if it reverted you get reverted (payment none: nothing was paid, so paying again is a new decision). Sellers keep proofs acceptable only for a while (the reference server: 10 minutes), so a late resubmit can be refused — that is settlement_failed with a notice; do not pay again then, tell the user and show the tx. Proofs are kept for 7 days. Returns the same shape as x402_fetch.

NameRequiredDescriptionDefault
txYesThe `tx` that x402_fetch returned for a payment the wallet broadcast itself (status pending, unknown or undelivered, or settlement_failed with a tx).

TDQS

A4.9/5.0
Behavior5/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Far exceeds the annotations: it states no new money moves and no approval is requested, describes the on-chain pre-check and each resulting status (pending, reverted with payment none), and discloses the seller acceptance window (~10 minutes on the reference server) and 7-day proof retention. The idempotent/read-only nature is confirmed in prose rather than left to the hints alone.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Purpose is front-loaded in the first clause, followed by the usage trigger and then the behavioral detail. The length is justified by the number of distinct outcomes (pending, reverted, refused) that the agent must handle correctly.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Although there is no output schema, the description states the return shape matches x402_fetch and enumerates every status the caller may encounter along with the correct reaction to each. Nothing an agent needs to invoke or interpret this tool is missing.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100%, so the baseline is 3, but the description adds real meaning: the tx must be one the wallet broadcast itself and is re-sent together with the saved challenge values to the same URL. That provenance and pairing context goes beyond the schema's bare field description.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb and resource (resubmits the on-chain proof of an x402 payment this wallet already broadcast) plus the goal (to get the content it paid for). It also distinguishes itself from the sibling x402_fetch by explicitly framing itself as the follow-up for a tx that came back without content.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines5/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Explicitly names the trigger condition: 'Use it when x402_fetch returned a `tx` without content (status pending, unknown or undelivered, or settlement_failed with a tx).' It also names the alternative (x402_fetch) and warns against paying again in the settlement_failed/refused cases.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

Tool Schema Changelog

Recent tool additions, removals, and schema changes observed during successful MCP inspections.

  1. 1 tool updatev0.5.0
    • Changedx402_fetch3 fields changed
      • addedInput schema / properties / body
        Added value: +{
        +  "additionalProperties": true,
        +  "description": "JSON object sent as the request body (not allowed with GET). Content-Type defaults to\napplication/json. The paid retry sends exactly the same body.",
        +  "type": "object"
        +}
      • addedInput schema / properties / headers
        Added value: +{
        +  "additionalProperties": {
        +    "type": "string"
        +  },
        +  "description": "Extra request headers as a JSON object of name → value. Payment headers, Host,\nContent-Length and connection headers are set by the wallet and are refused here.\nThe paid retry sends the same headers.",
        +  "type": "object"
        +}
      • addedInput schema / properties / method
        Added value: +{
        +  "description": "HTTP method: GET (default), POST, PUT, PATCH or DELETE. Many paid APIs (search, image\ngeneration) take POST with a JSON body. The paid retry uses the same method.",
        +  "type": "string"
        +}
  2. 1 tool updatev0.4.3
    • Addedx402_resubmit
  3. 4 tool updatesv0.4.1
    • Changedget_history2 fields changed
      • removedInput schema / properties / limit / default
        Removed value: -null
      • removedInput schema / properties / limit / nullable
        Removed value: -true
    • Changedlookup_agent4 fields changed
      • removedInput schema / properties / pay_to / default
        Removed value: -null
      • removedInput schema / properties / pay_to / nullable
        Removed value: -true
      • removedInput schema / properties / resource / default
        Removed value: -null
      • removedInput schema / properties / resource / nullable
        Removed value: -true
    • Changedrequest_payment6 fields changed
      • removedInput schema / properties / agent_id / default
        Removed value: -null
      • removedInput schema / properties / agent_id / nullable
        Removed value: -true
      • removedInput schema / properties / memo / default
        Removed value: -null
      • removedInput schema / properties / memo / nullable
        Removed value: -true
      • removedInput schema / properties / token / default
        Removed value: -null
      • removedInput schema / properties / token / nullable
        Removed value: -true
    • Changedx402_fetch4 fields changed
      • removedInput schema / properties / agent_id / default
        Removed value: -null
      • removedInput schema / properties / agent_id / nullable
        Removed value: -true
      • removedInput schema / properties / memo / default
        Removed value: -null
      • removedInput schema / properties / memo / nullable
        Removed value: -true
  4. 1 tool updatev0.4.0
    • Changedrequest_payment1 field changed
      • addedInput schema / properties / agent_id
        Added value: +{
        +  "default": null,
        +  "description": "Optional: the recipient's ERC-8004 agent number, if you know it from the service's own\ndocumentation or agent card. The wallet reads that agent's on-chain record and tells the\nuser whether the address you are paying is the one registered for that agent. A mismatch\nis the useful part — a match is not proof of anything, since anyone can register.\nLeave it out if you don't know it; a wrong number just produces a \"no such agent\" note.",
        +  "format": "uint64",
        +  "minimum": 0,
        +  "nullable": true,
        +  "type": "integer"
        +}
  5. 2 tool updatesv0.3.0
    • Addedlookup_agent
    • Changedx402_fetch1 field changed
      • addedInput schema / properties / agent_id
        Added value: +{
        +  "default": null,
        +  "description": "Optional: the seller's ERC-8004 agent number, if you know it from the service's own\ndocumentation or agent card. The wallet then reads that agent's on-chain record and shows\nthe user whether the payment address and the resource domain match what is registered.\nLeave it out if you don't know it — a wrong number just produces a \"no such agent\" note.",
        +  "format": "uint64",
        +  "minimum": 0,
        +  "nullable": true,
        +  "type": "integer"
        +}
  6. 5 tool updatesv0.2.0
    • First observedget_balances
    • First observedget_history
    • First observedget_wallet_status
    • First observedrequest_payment
    • First observedx402_fetch

TDQS

A4.3/5.0

Scored across 7 tools

Disambiguation4/5

Most tools are clearly distinct (request_payment, get_wallet_status, get_balances, get_history, lookup_agent). The only partial overlaps are request_payment vs x402_fetch (both trigger payments) and x402_fetch vs x402_resubmit, though the descriptions clearly delineate direct transfer vs paid API call vs proof resubmission without new money.

Naming Consistency4/5

Consistent snake_case verb_noun pattern (request_payment, get_wallet_status, get_balances, get_history, lookup_agent), with x402_fetch and x402_resubmit using a coherent namespace prefix. Minor deviation from pure verb_noun but overall predictable.

Tool Count5/5

7 tools is well-scoped for a wallet/payment server, with each tool earning its place. No redundant or filler tools.

Completeness4/5

Covers the core wallet lifecycle: payments, status/accounts, balances, history, x402 paid fetches with resubmission, and agent registry lookup. Minor gaps like account-switching (explicitly user-only) or explicit cancellation are reasonable omissions, but no major workflow dead ends.

Maintenance

ActivityActive
ResponsivenessUnresponsive

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